Marine Weather and Tide Forecast for Weskan, KS

UPDATE
Issued at 1238 AM MDT Wed Apr 23 2025

A subtle shortwave is moving onto the Plains currently which is forecast to lead to an uptick in showers across the area. An intensifying low level jet is also seen across the area which I continue to believe will continue to provide additional lift as well especially along the nose. Isentropic ascent in the 310K level is also forecast to increase starting around 09Z roughly along a Wallace to Gove county line and on south. 850mb moisture is also forecast to increase through the night from the ESE as a boundary lifts into the area. With all of this said continue to have around 20-30% confidence in some thunderstorms across southeast portions of the area starting as early as 09Z. Based on RAP forecast soundings with 1500 j/kg of MUCAPE and wind shear around 30 knots along with w with steep lapse rates would support some quarter to half dollar size hail. Confidence in severe weather for the CWA is only around 5-10% at this time as the better forcing may set up south and/or east of the area as well. I am also starting to see some fog/stratus potential this morning as a boundary stalls out across the area, at this time fog potential looks to favor eastern Colorado.

The early morning storms continues to bring some uncertainty to the forecast if they linger around and keep temperatures from warming up therefore keeping instability down and if any outflow boundaries emanate from it as that would help stabilize the atmosphere. Current expectations is for a boundary, perhaps a pseudo warm front/differential heating boundary to set up draped from roughly Graham county back towards Cheyenne county Colorado which will be the focus for storms to develop as moisture continues to pool up against the boundary from the southeast where dew points may reach into the mid 60s. A surface trough is also forecast to be in place across southeast Colorado which appears to be another focus for convective development as well. The RAP continues to show a potential higher impact day with higher amounts of CAPE (SBCAPE and MUCAPE around 3500 j/kg and along stronger shear around 40-45 knots. If this environment does pan out then any mature cell that could latch onto the warm front would support a very large hail (2+ inches) and a tornado threat as well, with the tornado threat maximizing during the early evening as a low level jet develops.
The NAM on the other hand has the warm front further south and the better moisture remain across SW Kansas. Some severe potential would remain possible as well but not as impactful with hail of quarter to ping pong ball the main hazard due to lesser CAPE to work with. The RAP also has a stronger 700mb jet which would also support more organization of the storms whereas the NAM has virtually weak 700mb winds.

Jumping to part 2 of all of this now is the surface trough across southeastern Colorado. Easterly upslope flow is forecast to be ongoing which will interact with the SW winds of this trough leading to another area of convection around the I-25 corridor with this moving to the east towards the CWA This activity appears to be more isolated to scattered in nature with hail around ping pong ball to golf ball size the main threat. Straight line hodographs are forecast to be present which would support to the splitting of cells. The current expectation is that numerous splitting of these cells into the evening will lead to additional cold pools that will be the source of further convection as the low level jet kicks and will merge with the eastern storms leading to an MCS that will move across the area.

This then leads into the next potential hazard which will be flooding potential. Due to the recent dryness overall flooding is overall not a huge concern. The continued question will be what the quality of the moisture be with the RAP advecting in low 60 dew points back to the Highway 385 corridor and the NAM keeping dewpoints in the low 50s. If the RAP does verify then PWATS may approach 1.25 inches which is well above the 90th percentile climatological values and may pose more of a locally enhanced hydro threat wherever training does occur at. The NAM is still around 1 inch PWATS which would lead me to think that more nuisance type flooding would be possible. The other part to note as well when it come to flooding potential is any storm which is a right mover which would favor tracking to the east has very slow Bunkers Storm Motion less than 10 knots which would also potentially further exacerbate flooding as well. Just something to be aware of before storms grow upscale in the evening as well.

Thursday may see another severe threat as yet another 700mb shortwave moves across the area along with continued dew points in the 50s across the entire area. The main question for the day will be how much will the atmosphere recover and cloud cover dissipates from the previous days storms. If temperatures can recover then hail around ping pong balls would be the main threat, however if the temperatures don't recover then the severe threat would be limited. An incoming cold front may lead to further convection through the evening and night which depending on what occurs today may lead to more flooding concerns for whomever sees the most rainfall.

SHORT TERM /THROUGH FRIDAY NIGHT/
Issued at 205 PM MDT Tue Apr 22 2025

Tonight...a subtle weather system embedded within nearly zonal flow aloft reaches parts of far eastern Colorado late this afternoon, continuing east across the remainder of the forecast area tonight. A secondary system moves out of southeast Colorado, supporting 20%-30% pops south of Interstate 70. Given a lack of strong elevated instability, severe weather is not expected. Chances for precipitation are in the 20%-30% range which may be optimistic. Low temperatures are forecast to be in the upper 30s to upper 40s.

Wednesday-Wednesday night...moisture below 700mb increases from the south/southeast during the day, remaining over the area during the night. A mid level dry slot is forecast to be over the area in the morning, continuing through mid afternoon before another weather system moves through the area from the southwest during the late afternoon and overnight hours. I've lowered pops quite a bit during the morning with a 20%-30% chance for showers east of Highway 27. As the 850-500mb layer becomes more favorable due to the approaching system, shower and thunderstorm chances increase into the 30%-60% range. Severe thunderstorms will be possible with all hazards possible. High temperatures are forecast to be in the upper 60s to upper 70s.

During the overnight hours, showers and thunderstorms become more widespread as upper jet divergence increases, promoting a large area of precipitation. Some excessive rainfall is possible as this system slowly moves to the northeast. Low temperatures are forecast to be in the lower 40s to lower 50s.

Thursday-Thursday night...with plenty of moisture below 700mb, including the boundary layer, its looking likely a generally cloudy day. I've tried to keep the precipitation chances fairly modest given an overall lack of deep moisture and lift. For now, pops are in the 50%-80% range, mainly during the morning hours. Overnight, another weather system may move through, providing deeper moisture through about 500mb. Shower and thunderstorm chances are in the 60%- 70% range. High temperatures are currently forecast to be in the 60 to 70 degree range. NAM model has temperatures in the lower 50s to lower 60s which is certainly possible if we're under widespread low clouds and showers. Low temperatures are forecast to be in the upper 30s to middle 40s.

Friday-Friday night...its looking to be a generally cloudy day given abundant low level moisture for clouds. These clouds continue overnight. With a mid level dry slot over the area during the day, we'll need to rely on the moisture below 700mb to produce our precipitation which is currently in the 20%-40% range during the day. Overnight, chances increase into the 50%-70% range as a weather system moves through from the southwest. High temperatures are forecast to be in the middle 50s to lower 60s with low temperatures in the 40s.

LONG TERM /SATURDAY THROUGH TUESDAY/
Issued at 133 PM MDT Mon Apr 21 2025

From the latest runs of the GFS and ECMWF, both sets of guidance are favoring the first half of the upcoming weekend as the best chances for precipitation across the region.

With SFC to 500mb ridging providing a blocking effect to the east to start off the weekend, the surface low and associated cold front will continue a slow trudge east into the region. This system in combination w/ a 500/700mb weak shortwave riding along the western edge of the upper ridge to the east, will make a slow trek north/northeastward into the northern Plains late Saturday on into Sunday.

Precipitation chances will also degrade from the west as a dry RH layer from 850-700mb comes in from the southwest ahead of a closed low in the Rockies. This will peak over the area on Monday before retreating south as the next round of precipitation chances works south.

For Saturday-Saturday night, dewpts in the lower to mid 50s ahead of the front, combined with decent PW values of 0.80-1.00" at least to the Colorado border with fuel shower and thunderstorm chances 60-70% during the day east of the Colorado border w/ 40-50% west. By Saturday night there is now a 50-60% chance east of Highway 25, with a 25-40% chance west w/ the drier air working into the region.

Sunday-Sunday night, the system continues to lift northward w/ still a 20-40% chance of precipitation, especially during the daytime hours. Enough instability still present especially east of Highway 25 w/ dewpts in the 50s/60s to keep a mention of thunder in the forecast.

Monday into Tuesday night, a 20-30% chance for mainly showers expands from the north to the south as wrap-around surface moisture from the exiting low to the north interacts with 500-700mb trough on the backside of the system. There could be enough dry air south of I- 70 to bring about increased fire danger on Monday afternoon, and will have to be monitored

For temps, highs on Saturday are going to range from the upper 60s east into the lower and mid 70s west. The difference is due to the more extensive cloud cover/chances for precipitation as the system lifts off to the north and east. Much warmer on Sunday with lower to mid 80s expected area-wide. Trending cooler going into next week w/ monday having mainly 70s west of a line from mainly Culbertson, Nebraska southwest to Tribune, Kansas. East of this line, upper 70s to lower 80s. By Tuesday, a wide range is expected w/ mainly 60s in northeast Colorado, and mainly lower to mid 70s east of there.

Overnight lows for Saturday and Sunday nights will have a wide range from the mid and upper 40s in northeast Colorado, to lower to mid 50s for KS/NE. Trending slightly colder for next Monday and Tuesday nights with mid 30s to around 40F along/west of Highway 27, coldest in northeast Colorado. East of there, 40s will persist. Warmest locales will be east of Highway 83.

AVIATION /12Z TAFS THROUGH 12Z THURSDAY/
Issued at 337 AM MDT Wed Apr 23 2025

VFR conditions are forecast to start the period with mainly easterly winds across the area through the day. Still can't completely rule out some spotty fog with lowering dew point depressions for KGLD but confidence was not high enough to introduce in the TAF. Spotty showers are forecast to develop near the KMCK terminal for the first few hours of the TAF period but not anticipating any impacts. Continuing to monitor for the potential for showers and storms this afternoon and through the night Wednesday. Some of the storms may be strong to severe.
Increasing confidence in MVFR to potentially IFR ceilings towards the end of the period. Continuing the AMD NOT SKED as there has been intermittent communications issues with the reporting of the ASOS through the night thus far.



GLD WATCHES/WARNINGS/ADVISORIES
KS...None.
CO...None.
NE...None.